It is a given that high-quality research on environmental health problems must involve the use of state-of-the-art biostatistical and quantitative epidemiological methods. The mission of the Biostatistics and Epidemiologic Methods Facility Core (BEMFC) is to facilitate Center research activities by providing expertise to Center researchers in the important areas of research study design and data analysis. In addition, BEMFC personnel will develop new and innovative biostatistical and epidemiological methods as needed to address non-standard design and analysis issues that arise. Since such design, analysis, and methodologic development issues will be an integral part of the research efforts in all of the research Cores in this Center, it is an efficient and cost-effective allocation of resources within the Center to assign these related activities to this particular facility Core. The aims of this Core are to: a) to help Center investigators with the optimal design of research studies; b) to help Center investigators with state-of-the-art analyses of research data; c) to develop, when needed, innovative biostatistical and epidemiologic methods to address non-standard design and analysis issues; and, d) to serve as a resource to Center researchers for software, educational, and library needs as they relate to biostatistical and quantitative epidemiological methods.